Mental Health Act (1983)

Last reviewed 01/2018

Most patients who require inpatient care will agree to hospital admission and become 'informal' patients. However, a minority of patients - about 5% - will require compulsory admission and detention. The majority of such patients are detained under the Mental Health Act of 1983 and are often termed 'sectioned' - in reference to the Section of the Mental Health Act under which they are detained.

All compulsorily detained patients should be suffering from a mental disorder which merits detention in hospital in the interests of their own health or safety, or the safety of others.


  • the Mental Health Act 1983 has been amended by the Mental Health Act 2007 (but is still termed the Mental Health Act 1983)
      • the Mental Health Act 2007 has change the definition of Mental Disorders covered by the Mental Health Act
        • now defined as "any disorder or disability of the mind"
        • simplified definition now applies to all sections of the Act
        • four forms of mental disorder (mental illness, mental impairment, severe mental impairment and psychopathic disorder) have disappeared
          • potentially means some people previously excluded are now included e.g. there may be some people with an acquired brain injury who were not covered by the term "mental impairment or severe mental impairment" who could now benefit from the protections of the Act
    • there are two exemptions specifically referred to:
      • Learning Disability
        • a person with learning disability may be only detained if that disability is associated with abnormally aggressive or seriously irresponsible conduct. This does not, of course, preclude the use of compulsion for people who have another form of mental disorder (such as a mental illness) in addition to their learning disability
        • applies to all those sections that relate to longer-term compulsory treatment or care for a mental disorder (in particular section 3, section 7 (Guardianship), section 17A (Supervised Community Treatment) and forensic sections under Part 3 of the Act)
      • Dependence on alcohol or drugs
        • refers only to dependence and does not exclude the effects of substances, such as intoxication, psychosis and delirium
      • note that the previous exemptions for "promiscuity or other immoral act" have not been included in the amendments made by the 2007 Mental Health Act
        • means that persons diagnosed with paedophilia can be detained in hospital by virtue of that alone
    • the Act makes it clear that professionals, including doctors, are expected to follow the guidance of the Code of Practice, or explain why they haven't done so
    • the 2007 Act provides a new provision to allow Supervised Community Treatment. This allows a patient detained on a treatment order to receive their treatment in the community rather than as an in-patient
      • allow a small number of patients who currently disengage from support once discharged from hospital to be cared for in the community, subject to the possibility of being recalled to hospital if necessary. This is to ensure they continue to get the treatment they need. There is no lower age limit